Total Bolt In Astro T5 OD Trans (250 I6) All GM Off the Shelf Parts-1965 C10 SBSS

[Sharps40]

Updates to post 11. New 24 tooth speedo gear modified to fit and installed. Test drive tonight. Hope it works!

[Sharps40]

Seems to be working good. Made a 120 mile round trip to hunting camp. It was a bit sticky starting out but loosened up and seems to work pretty good. A touch jumpy occasionally at high speed but it was that way before. 24 teeth is still about 5% off. So, 60 indicated is about 56 to 57 actual. Good enough for now while I debate whether to go back to the unmodified 20 tooth driven gear with a ratio reducer or a gauge change up at the dash with an electric speedo.

But,.....70 mph on the interstate is a joy, taching about 2500ish rpm. 60 mph tachs 2250 rpm. Compared to the old whiney peanut trans, its quite as a library in the cab...well, cept for the muffle and the wind noise and the wipers and.......

[Sharps40]

As for driving.....BEATS DA HELL OUTTA THE OL PEANUT! No Doubt! They shoulda come factory with a 5 speed but its nice to know the compatibility is there to use 1980s and 1990s parts to get the job done w/o modification.

A bit of tuning to do when the motor is finally broken in but I think we are nearly ready for the first cross country trip this coming year.

[Sharps40]

This is exactly what a T5 sounds like on the interstate at 70 mph.

Gear Jammer - YouTube

[Sharps40]

Update on the speedometer driven gear and accurate speedo readings.

Given the gear tooth counts/ratios (rear and trans speedo drive gear) listed above I had sought a 25 tooth driven gear to make the speedometer accurate. This gear is no longer avaialble. In any even, as I found out later, it woulda been too large in diameter for my 9 tooth speedo drive gear.

Knowing that each tooth made about a 5% difference in speed indicated and knowing how much I was off, I located a 24 tooth driven gear with help from a member here. Again, it was too large in diamter (there are three diameters, depending on tooth count) and the T5 with a 9 tooth drive gear takes the smallest diameter but may allow insertion of the middle diameter gear.

In any event, I modified the diameter and v groove depth of the 24 tooth gear and used it for a while with some satisfaction but still not accurate enought to suit me.

So I reinstalled the 20 tooth driven gear that came with the trans (speedometer way too fast, 24 to 25ish %!) and ordered a ratio adapter as indicated above. Close, very close but still off the mark by the tune of just over 5%.

Finally, success. Dropped in the new 19 tooth driven gear of middle diameter. No modification to diameter or tooth depth needed. With the off the shelf ratio adapter the math indicates I should be within 1% or so of dead on.

The visual at the speedo, compared to Garmin, is dead on!

Remember, if your garmin is like mine, ye'll have to hold steady speed for 10 seconds or so to let the data catch up to the screen. Its a long way from ground to satallite to ground again.

Also, given the potential wear in the entire speedo system (the gauge is old) I found my measurements to be most accurate at 40 to 70 mph, with the garmin and the speedo agreeing what looks like dead on at those speeds.

Good enough and done!

[Blue666]

Sharps, This is an excellent write up and I think the T5 is a great upgrade for our trucks. After all the time I spent looking for parts in a junk yard or on the web, I can't recall ever seeing a 5 speed Astro. I have seen tons of s-10's with a 4.3 liter T-5 but never an Astro set up for the T-5.

How many were made & how much different is the Astro T-5 from the S-10 T-5?

Thanks,

[Sharps40]

Contact lugnutz65. He found one recently and compares it on his site to the WC Camaro and the S10.

Gearing is different, fist is 3.5, way better than the 4.0ish of the s10. It dosn't feel granny gear. Also, the OD is .76 to 1 which works great for my 3.73 rear, I6 and 27.4" tall tires. Basically, about 750 fewer rpms.

I think the astro transmissions are in the astros from 84ish to about 1990/92ish. Not a lot of em were made but with an S10 tail housing, I love it. This install was total bolt in, no heavy modifications except for ordering a new drive shaft and uses all GM or GM on the shelf parts. I can get the entire rig serviced anywhere in the USA.....no good mechanic should be afraid to wrench on it since they can get everything off the shelf.

The notable strength of the Astro T5 for me was direct bolt on to the 65 bell housing and except for the driveshaft total availability/use of either GM or GM spec on the shelf components. With a properly sized driveshaft, this could be total back yard/small wrenches installation.

As for differnt....Langdon says the Camaro V8 T5 and Astro are the ones to use behind our sixes with the v8 camaro WC T5 becoming very expensive and harder to find parts for. (I havel elsewhere noted some folks easily adapting Ford T5s to our belhousings with very at home acheivable/home made adapters and some drilling.)

I think Mr. Langdon recognizes the S10 t5s are used a lot in our trucks but describes the S10 T5 asd generally designed for a 150"ish 4 cylinder and an appropriate amount of abuse, with the Camaro/Astro T5 being sized/absuable by larger engines. He clarified abuse as employee drivers/burnouts/wheel hop all as the severest abuse factors.

[Sharps40]

Here is the nuts and bolts of one installation of Ford T5 to early Chevy Truck Belhousing. As indicated, welding is not really required. Indexing ring could likely be made at home of suitably thick flat stock, heated and bent around and then put into place, ala the opposite of putting iron tires on a wooden wagon wheel or hoops on a barrel.

http://www.mgexp.com/phorum/read.php?40,2495913

Given input shaft lengths and throwout bearing sleeve lengths, there may be some mods needed for the front of the musting T5, perhaps even hand cutting longer splines.....I think most of the Mustench T5s were around 7"+ long....but again.....even if ya had to I think ya can come up with a spacer at home that take care of that issue too.

[Blue666]

I just did a quick search on Astro T5 (and variations) via craigslist for Charlotte, Atlanta, Birmingham & Nashville. I searched both vehicles & parts, I found one complete vehicle in Atlanta. They seem to harder to find than winning Powerball ticket.

In addition to the favorable gearing, this T5 has the shifter located 2.5 inches back from the S-10 shifter location. Still keeps it out of the seat but very little chance to hit the dash or A/C.

[Old Bleu]

Blue666, I also installed a T5 in my truck a few months back. I bought a World ZClass S10 unit from Tom Langdon. It required the spacer and a shrotened driveshaft, but other than that, it was pretty straughtforward.

As Sharps mentioned, you might want to contact LugNutz65 on this site. He is in Columbia, SC, and seems to have developed an addiction to T5's! Last time I was in touch with him, he had a number of units, and would likely be a good resource in finding a T5. Catch him at the right time, and his wife might even make him sell you one.

[Sharps40]

Originally Posted by Blue666

I just did a quick search on Astro T5 (and variations) via craigslist for Charlotte, Atlanta, Birmingham & Nashville. I searched both vehicles & parts, I found one complete vehicle in Atlanta. They seem to harder to find than winning Powerball ticket.

In addition to the favorable gearing, this T5 has the shifter located 2.5 inches back from the S-10 shifter location. Still keeps it out of the seat but very little chance to hit the dash or A/C.

Call Tom Langdon at Stovebolt Engine Company in MI. I got my astro T5 totally overhauled and with the short shift kit for $670 and 53 freight. He gets em in, go's over your needs, has em overhauled and sends em to ya. I'm totally happy with mine.

Seems like bucks but $350 at a yard, plus pullin it + rebuild kit and labor and yer at the same amount. This way, no dirty fingers till ya actually clean off underneath the truck.

[Sharps40]

Additonal options....this is pricy but looks like an easy way to put a more available Ford T5 on a small block chevy...plus ya can get the ford with a 3.35 first gear and some different ODs .... Pretty sure ya run a ford clutch on the chevy pressurplate and an adapter pilot bushing. Again, some research needed but it looks like its all bolt in. Since yer changein the driveshaft, the ford output spline is not an issue, simply put the right yoke on the shortened driveshaft. Can't say where a ford shifter falls for bench seat.....research.

http://americanpowertrain.com/i-8426...o-ford-t5.html

Here's another for the gm to ford at $100 less....research needed.

http://www.riley-auto.com/ADAPTERS.html

[Sharps40]

Well, lugnutz didn't use that astro T5 on his project, maybe ya can talk em into rebuildin it and sellin it to ya......

Remember, per Tom Langdon at Stovebolts, ATF in all of them....No gear oil no matter what "They" say on the innerwet....

[Sharps40]

Originally Posted by Blue666

I just did a quick search on Astro T5 (and variations) via craigslist for Charlotte, Atlanta, Birmingham & Nashville. I searched both vehicles & parts, I found one complete vehicle in Atlanta. They seem to harder to find than winning Powerball ticket.

In addition to the favorable gearing, this T5 has the shifter located 2.5 inches back from the S-10 shifter location. Still keeps it out of the seat but very little chance to hit the dash or A/C.

Yeah, its 2.5 inchs back and about 12 inches left toward the driver....look on lugnutz web site, he's got pics of the Astro T5 with that big offset shifter assembly....yer gonna want either camaro or S10 tail shaft housing for buckets or bench. That Astro shifter linkage is a cobbled together original GM nightmare and will come up thru the floor about where yer right leg is tryin to press the gas!

As for seat and dash clearance I copied Lugnuts shifter pattern and adapted it to me for comfort/easy reach. With the short shifter Langdon put in, its long/tall and easy to grab and clears dash and me/shortlegs/seat pretty far forward....pics are above.

[Sharps40]

Oh yeah, the price of my Langdon supplied Astro t5 included the S10 tail shaft cover with provision for mech speedo. If you go thru him, make sure ya talk tire size/final gear out back so you can get his rebuilder to put in an appropriate speedo drive and driven gear and be more accurate on the first try, stead of swappin around driven gears and ratio reducers.

[Sharps40]

Just back from the shop. Thought we had a broken throwout bearing. Crunch on the top, stick at the bottom, looked like the race had separated from the bearing. Word is in....scoped it, repeated the crunches a bunch.......but all looked well.

Scope showed a bit too little free travel for the combination....short sleeve on the T5 inputshaft and the short length S10 bearing would ride just far enough forward to occasionally cock at the end of the sleeve, catching on the way back....Moveing free travel out to 1.5" fixed that problem and perfect smooth function.

As for the crunch at the top, occasionally the new heim jointed linkage would rub all the steel under the dash. Shimmed the heim joint out just a bit and that crunch is gone too.

Rides like a dream.

New mechanic at the shop looked it over and made the adjustments.....all free of charge as follow up on the T5 and new engine installation.

And he said, "You wouldn't expect it but that old truck, old as it is, is way smoother and stronger than it should be. Its a great package."

We took it as a complement. Gotta stop tomorrow and get the shop some good Makers Cigars for the upcoming nice weekend weather.

All is well. I spose when yer runnin a swap out like this with parts from the mid 60s thru the mid 90s ya gotta plan for a couple xtra adjustments to tweak it all in.

[Eric15chevys]

One of my friends at work did one of these on his 57 chevy that had a 70 250 in it. He loves it. Last month he drove it down to Fayetville from Newport News. He said the over drive is so nice.

[Sharps40]

Overdrive is da bom!!!

[Larry64]

You got that right. For an I6 230 it makes highway driving cool. T5's rock.
Larry

[Sharps40]

Just over 6000 miles down the road with the new engine and the Astro T5. Some things I've figured out just as an update.

Once the 250 is tuned properly, it pulls and pulls and pulls with the T5.

Best fuel mileage, about 18.5 mpg on midgrade comes in when operating mostly on the highways. Speeds up to 60ish mph with lots of time in overdrive give this level of economy. 65 and up and the fuel mileage drops to just a whisker under 17 mph. Not bad either way....rolling down the road at 60 and I tach just under 2200 rpm, under 2700 rpm at 70 mph. Any of those speeds is quite comfortable.

The rebuilt T5 is noticably quieter in all gear than the peanut trans.

While the engine and trans combination will pull well from silly low rpm in about any of the gears, the truck is happiest running steadily from 2000 to 2400 rpm. So, we tool around most of the time at the top of each gear and its as nimble and responsive as a 49 year old 3600 lb truck can be.

Specify the final gear and tire sizes when you get your T5 rebuilt. There is a 7 tooth and 9 tooth speedometer drive gear. I have the 9 and with the 3.73 out back, it took a 19 tooth driven gear and a ratio reducer to finally acheive an almost dead on accurate reading at the speedometer. Many of the driven gears needed to acheive accurate readings with the 9 tooth drive gear are either too large in diameter to work or just not avaialble any more. For most folks with a 3.73 out back and 27.4" tall tires, I think ye'd have better luck with the 7 tooth drive gear. But, fortunatly, the ratio reducers are wonderfully functional devices, if a bit expensive at $60ish + shipping. If you can't specify speedo gearing up front the easiest way to work the issue after the installation is to use the garmin, capture your indicated and actual speeds at 40, 50, 60 and 70 mph and then call a good speedo shop for the right combination of driven gear and/or ratio reducer/increaser.

The speedometer driven gear bullet is a leak source, even with new internal and external seals.....I blu-gooed it in place....leak stopped.

Dex/Merc trans fluid is a bit difficut to find. But I noted some supplies at WallHell and picked up a few extra bottles for future use.

Install the short throw shifter assembly.....with a bend or two in the shifter handle that lays the ball close to yer right leg in 2nd, the reach is smooth easy in all the gears and helps a lot with clearance issues between a bench seat an the dash.

Do not use the multipiece (pressed together 3 piece clutch release bearing) as it will separate. There are 2 short bearings from Oreillies for the mid 70s era trucks, I believe they provided me the Master Pro 614018 short, pressed together bearing for $13 and it separated into inner sleeve, outer sleeve and the bearing is loose on the outer sleeve. I'll be replacing it with the National bearing of the same part number, pics indicate it appears to be a single piece bearing coller with the bearing pressed on so, with luck, more strength, no redo's. But once the old bearing is out, I'll post up pics of both and confirm the part numbers. Hopefully some combination of long bolts a sling and a jack will allow me to slide the T5 back 6 or so inches, drop out the old and insert the new. Its a one man shop and no tranny jack so I'm lookin to be creative/bring what I got for the R&R.

[TJ's Chevy]

Great info Rich!

[Lugnutz65]

Sharps40,
What ratio reducer do you have? I have a Stewart Warner 0.7333333 reducer but I don't know if I'll need it yet or not.

[Sharps40]

Originally Posted by Lugnutz65

Sharps40,
What ratio reducer do you have? I have a Stewart Warner 0.7333333 reducer but I don't know if I'll need it yet or not.

Ill check. .7333333 is the same as 26.7 percent. 26.7 reduction is what I have. Gimmie a day or three ta check papers. Headin out fer turkey n trout. Me n John Lee is headin fer the mtns!

[Lugnutz65]

Mine looks like this.

[Sharps40]

Looks bout the same as mine. If you have a red speedo drive gear in the T5, its a 9 tooth. The only other one is 7 tooth....most are red 9s.

Coupled with a 3.73 out back and 27.4" tall tires you are most likely like me, going to need....

1 A totally unavailable and too big in diameter if it was available, 25 tooth driven gear.

2. A proper diameter (small to medium should fit fine, the T5 is sposed to take the small dia driven gear) driven gear wif 19 teeth and the 26.7% ratio reducer. I think I put the ratio I used over in the john lee jr thread. I'll check.